The present invention relates to current sensing, and in particular, to switching systems and methods with current sensing. Some switching regulator systems utilize a voltage control loop and a current control loop to provide a stable output voltage source. The voltage loop provides a regulated voltage value and responds to changes in output voltage. The current loop may respond to changes in peak current. This type of current loop may react quickly to changes in the peak current and thereby allow the switching regulator system to provide better regulation under transient load conditions such as a step response on the output of the switching regulator system, for example. A current mode loop may allow for a feed-forward effect in which the current change is sensed and the peak current mode loop responds prior to the voltage significantly diverting from the regulated voltage value. A current mode control loop may help simplify the required compensation for the switching regulator system.
Current mode control requires current sensing. Directly sensing the peak currents has historically been problematic since the switching voltages associated with the load inductor in switching regulator systems may contain transient voltages well above the safe operating range of the sense electronics required to sense the peak current. This presents a reliability problem for the regulator system. Indirectly sensing the peak current by using a filter circuit or scaling circuit to provide a corresponding current or voltage is problematic due to the inaccuracies the circuits introduce. These inaccuracies make performance less predictable over manufacturing tolerances.
Thus, there is a need for improved current sensing. The present invention solves these and other problems by providing switching systems and methods with current sensing.